A law enforcement officer watches on Aug. 17, 2014, as smoke is fired to disperse a crowd protesting the shooting of teenager Michael Brown last Saturday in Ferguson, Mo. / Charlie Riedel, AP

by Yamiche Alcindor, USA TODAY

by Yamiche Alcindor, USA TODAY

FERGUSON, Mo. - Seven people were arrested and one person was shot early Sunday as police and protesters clashed again in a haze of tear gas despite a curfew that took effect at midnight.

Missouri State Highway Patrol Capt. Ronald Johnson said the shooting victim was in critical condition. Johnson said police used tear gas in an effort to reach the wounded person, but that other protesters already had taken the shooting victim to the hospital, Johnson said.

It was not clear who fired the shot, but Gov. Jay Nixon said Sunday that no police officers fired their guns during or after the protest.

Seven people will face charges of failure to disperse. Early Sunday, members of the media were ordered to remain in the parking lot of the Ferguson Market or risk arrest.

The curfew, put in place by Nixon, was designed to quell ongoing unrest in the St. Louis suburb since the Aug. 9 fatal police shooting of Brown by officer Darren Wilson. Police also released a surveillance video purporting to show Brown stealing from a convenience store and roughing up its clerk about 15 minutes before the confrontation with Wilson.

"We were unaware they were going to release it, and we certainly were not happy with that being released," Nixon told ABC's This Week on Sunday. "It appeared to cast aspersions on a young man that was gunned down in the street. It made emotions raw."

Also Sunday, the Justice Department said it would arrange for an another, "independent" autopsy of Brown's body "due to the extraordinary circumstances involved in this case and at the request of the Brown family."

The St. Louis County Medical Examiner's autopsy concluded that Brown died of gunshot wounds, but other details have not been released.

The curfew expired at 5 a.m. local time. Crowds had dwindled significantly leading up to the curfew, but remaining protesters - chanting "No justice! No curfew!" - refused to leave the area. Some stood with their hands up, the emblematic pose used by many protesters to characterize the position witness have said Brown had assumed when he was fatally shot.

"We ready. We ready. We ready for y'all, " people chanted, while others screamed, "We are Mike Brown."

About 45 minutes past the curfew deadline, armored tactical vehicles approached the crowd in an effort to disperse those that refused to leave West Florissant Avenue, a main thoroughfare and scene of numerous protests.

"You are in violation of a state-imposed curfew. You must disperse immediately. Failure to comply may result in arrest," officers said through a loudspeaker.

As officers put on gas masks, a chant from the distant crowd emerged: "We have the right to assemble peacefully."

Police used smoke and tear gas to push back the crowd of protesters, and officers also carried rifles, gas masks, plastic handcuffs and helmets.

Police also brought in armored tanks after learning of some disturbances at Reds Barbecue, a local restaurant. En route, officers encountered a man who flashed a handgun and appeared in the middle of the street as armored vehicles approached the crowd of protesters, Johnson said.

Johnson said someone also fired at a patrol car, but no officers were injured.

Johnson defended the use of military-style armored cars and tactical units dressed like soldiers. The situations faced by police justified their actions and tactics, he said.

"We have a shooting victim that is in critical condition that may lose their life," Johnson said. "We had a subject standing in the middle of the road with a handgun. We had a police car shot at tonight."

St. Louis Alderman Antonio French, who represents the 21st Ward, said he and other community members pleaded with everyone to obey the curfew.

"Some of the guys didn't want to be told to leave," French said. "There was no convincing them. They wanted to do civil disobedience."

Umar Lee, 39, an independent journalist, who said he grew up in North St. Louis, saw protesters were throwing canisters of gas deployed by the police back at the police during the tense clashes.

"This is surreal to see my hometown look like Gaza," Lee said. "I just pray for peace in my community."

Nixon, however, told CNN on Sunday he was encouraged by the most recent events.

"Thousands of people spoke, thousands of people marched, not a single gunshot from police last night," Nixon said. "We are trying to use the least amount of force to provide people with protection."

Nixon also said it was important to have thorough local and FBI investigations completed as soon as possible.

"Attorney General Holder said he is putting 40 agents into the area to accelerate the process," Nixon said. "It's important to get this right. It has to be transparent justice, it has to be thorough justice."